/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
/**
 * Copyright (c) 2004-2011 QOS.ch All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining a  copy  of this  software
 *  and  associated  documentation files  (the "Software"), to  deal in  the Software without
 * restriction, including without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to permit persons to whom the
 * Software  is furnished to do so, subject to the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be included in all copies or
 * substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND, EXPRESS OR  IMPLIED,
 * INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF MERCHANTABILITY,    FITNESS    FOR    A
 * PARTICULAR    PURPOSE    AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
package io.netty.util.internal.logging;

import java.text.MessageFormat;
import java.util.HashSet;
import java.util.Set;

// contributors: lizongbo: proposed special treatment of array parameter values
// Joern Huxhorn: pointed out double[] omission, suggested deep array copy

/**
 * Formats messages according to very simple substitution rules. Substitutions
 * can be made 1, 2 or more arguments.
 * <p/>
 * <p/>
 * For example,
 * <p/>
 * <pre>
 * MessageFormatter.format(&quot;Hi {}.&quot;, &quot;there&quot;)
 * </pre>
 * <p/>
 * will return the string "Hi there.".
 * <p/>
 * The {} pair is called the <em>formatting anchor</em>. It serves to designate
 * the location where arguments need to be substituted within the message
 * pattern.
 * <p/>
 * In case your message contains the '{' or the '}' character, you do not have
 * to do anything special unless the '}' character immediately follows '{'. For
 * example,
 * <p/>
 * <pre>
 * MessageFormatter.format(&quot;Set {1,2,3} is not equal to {}.&quot;, &quot;1,2&quot;);
 * </pre>
 * <p/>
 * will return the string "Set {1,2,3} is not equal to 1,2.".
 * <p/>
 * <p/>
 * If for whatever reason you need to place the string "{}" in the message
 * without its <em>formatting anchor</em> meaning, then you need to escape the
 * '{' character with '\', that is the backslash character. Only the '{'
 * character should be escaped. There is no need to escape the '}' character.
 * For example,
 * <p/>
 * <pre>
 * MessageFormatter.format(&quot;Set \\{} is not equal to {}.&quot;, &quot;1,2&quot;);
 * </pre>
 * <p/>
 * will return the string "Set {} is not equal to 1,2.".
 * <p/>
 * <p/>
 * The escaping behavior just described can be overridden by escaping the escape
 * character '\'. Calling
 * <p/>
 * <pre>
 * MessageFormatter.format(&quot;File name is C:\\\\{}.&quot;, &quot;file.zip&quot;);
 * </pre>
 * <p/>
 * will return the string "File name is C:\file.zip".
 * <p/>
 * <p/>
 * The formatting conventions are different than those of {@link MessageFormat}
 * which ships with the Java platform. This is justified by the fact that
 * SLF4J's implementation is 10 times faster than that of {@link MessageFormat}.
 * This local performance difference is both measurable and significant in the
 * larger context of the complete logging processing chain.
 * <p/>
 * <p/>
 * See also {@link #format(String, Object)},
 * {@link #format(String, Object, Object)} and
 * {@link #arrayFormat(String, Object[])} methods for more details.
 */
final class MessageFormatter {

  private static final String DELIM_STR = "{}";
  private static final char ESCAPE_CHAR = '\\';

  /**
   * Performs single argument substitution for the 'messagePattern' passed as
   * parameter.
   * <p/>
   * For example,
   * <p/>
   * <pre>
   * MessageFormatter.format(&quot;Hi {}.&quot;, &quot;there&quot;);
   * </pre>
   * <p/>
   * will return the string "Hi there.".
   * <p/>
   *
   * @param messagePattern The message pattern which will be parsed and formatted
   * @param arg            The argument to be substituted in place of the formatting anchor
   * @return The formatted message
   */
  static FormattingTuple format(String messagePattern, Object arg) {
    return arrayFormat(messagePattern, new Object[]{arg});
  }

  /**
   * Performs a two argument substitution for the 'messagePattern' passed as
   * parameter.
   * <p/>
   * For example,
   * <p/>
   * <pre>
   * MessageFormatter.format(&quot;Hi {}. My name is {}.&quot;, &quot;Alice&quot;, &quot;Bob&quot;);
   * </pre>
   * <p/>
   * will return the string "Hi Alice. My name is Bob.".
   *
   * @param messagePattern The message pattern which will be parsed and formatted
   * @param argA           The argument to be substituted in place of the first formatting
   *                       anchor
   * @param argB           The argument to be substituted in place of the second formatting
   *                       anchor
   * @return The formatted message
   */
  static FormattingTuple format(final String messagePattern,
      Object argA, Object argB) {
    return arrayFormat(messagePattern, new Object[]{argA, argB});
  }

  /**
   * Same principle as the {@link #format(String, Object)} and
   * {@link #format(String, Object, Object)} methods except that any number of
   * arguments can be passed in an array.
   *
   * @param messagePattern The message pattern which will be parsed and formatted
   * @param argArray       An array of arguments to be substituted in place of formatting
   *                       anchors
   * @return The formatted message
   */
  static FormattingTuple arrayFormat(final String messagePattern,
      final Object[] argArray) {
    if (argArray == null || argArray.length == 0) {
      return new FormattingTuple(messagePattern, null);
    }

    int lastArrIdx = argArray.length - 1;
    Object lastEntry = argArray[lastArrIdx];
    Throwable throwable = lastEntry instanceof Throwable ? (Throwable) lastEntry : null;

    if (messagePattern == null) {
      return new FormattingTuple(null, throwable);
    }

    int j = messagePattern.indexOf(DELIM_STR);
    if (j == -1) {
      // this is a simple string
      return new FormattingTuple(messagePattern, throwable);
    }

    StringBuilder sbuf = new StringBuilder(messagePattern.length() + 50);
    int i = 0;
    int L = 0;
    do {
      boolean notEscaped = j == 0 || messagePattern.charAt(j - 1) != ESCAPE_CHAR;
      if (notEscaped) {
        // normal case
        sbuf.append(messagePattern, i, j);
      } else {
        sbuf.append(messagePattern, i, j - 1);
        // check that escape char is not is escaped: "abc x:\\{}"
        notEscaped = j >= 2 && messagePattern.charAt(j - 2) == ESCAPE_CHAR;
      }

      i = j + 2;
      if (notEscaped) {
        deeplyAppendParameter(sbuf, argArray[L], null);
        L++;
        if (L > lastArrIdx) {
          break;
        }
      } else {
        sbuf.append(DELIM_STR);
      }
      j = messagePattern.indexOf(DELIM_STR, i);
    } while (j != -1);

    // append the characters following the last {} pair.
    sbuf.append(messagePattern, i, messagePattern.length());
    return new FormattingTuple(sbuf.toString(), L <= lastArrIdx ? throwable : null);
  }

  // special treatment of array values was suggested by 'lizongbo'
  private static void deeplyAppendParameter(StringBuilder sbuf, Object o,
      Set<Object[]> seenSet) {
    if (o == null) {
      sbuf.append("null");
      return;
    }
    Class<?> objClass = o.getClass();
    if (!objClass.isArray()) {
      if (Number.class.isAssignableFrom(objClass)) {
        // Prevent String instantiation for some number types
        if (objClass == Long.class) {
          sbuf.append(((Long) o).longValue());
        } else if (objClass == Integer.class || objClass == Short.class || objClass == Byte.class) {
          sbuf.append(((Number) o).intValue());
        } else if (objClass == Double.class) {
          sbuf.append(((Double) o).doubleValue());
        } else if (objClass == Float.class) {
          sbuf.append(((Float) o).floatValue());
        } else {
          safeObjectAppend(sbuf, o);
        }
      } else {
        safeObjectAppend(sbuf, o);
      }
    } else {
      // check for primitive array types because they
      // unfortunately cannot be cast to Object[]
      sbuf.append('[');
      if (objClass == boolean[].class) {
        booleanArrayAppend(sbuf, (boolean[]) o);
      } else if (objClass == byte[].class) {
        byteArrayAppend(sbuf, (byte[]) o);
      } else if (objClass == char[].class) {
        charArrayAppend(sbuf, (char[]) o);
      } else if (objClass == short[].class) {
        shortArrayAppend(sbuf, (short[]) o);
      } else if (objClass == int[].class) {
        intArrayAppend(sbuf, (int[]) o);
      } else if (objClass == long[].class) {
        longArrayAppend(sbuf, (long[]) o);
      } else if (objClass == float[].class) {
        floatArrayAppend(sbuf, (float[]) o);
      } else if (objClass == double[].class) {
        doubleArrayAppend(sbuf, (double[]) o);
      } else {
        objectArrayAppend(sbuf, (Object[]) o, seenSet);
      }
      sbuf.append(']');
    }
  }

  private static void safeObjectAppend(StringBuilder sbuf, Object o) {
    try {
      String oAsString = o.toString();
      sbuf.append(oAsString);
    } catch (Throwable t) {
      System.err
          .println("SLF4J: Failed toString() invocation on an object of type ["
              + o.getClass().getName() + ']');
      t.printStackTrace();
      sbuf.append("[FAILED toString()]");
    }
  }

  private static void objectArrayAppend(StringBuilder sbuf, Object[] a, Set<Object[]> seenSet) {
    if (a.length == 0) {
      return;
    }
    if (seenSet == null) {
      seenSet = new HashSet<Object[]>(a.length);
    }
    if (seenSet.add(a)) {
      deeplyAppendParameter(sbuf, a[0], seenSet);
      for (int i = 1; i < a.length; i++) {
        sbuf.append(", ");
        deeplyAppendParameter(sbuf, a[i], seenSet);
      }
      // allow repeats in siblings
      seenSet.remove(a);
    } else {
      sbuf.append("...");
    }
  }

  private static void booleanArrayAppend(StringBuilder sbuf, boolean[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void byteArrayAppend(StringBuilder sbuf, byte[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void charArrayAppend(StringBuilder sbuf, char[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void shortArrayAppend(StringBuilder sbuf, short[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void intArrayAppend(StringBuilder sbuf, int[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void longArrayAppend(StringBuilder sbuf, long[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void floatArrayAppend(StringBuilder sbuf, float[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private static void doubleArrayAppend(StringBuilder sbuf, double[] a) {
    if (a.length == 0) {
      return;
    }
    sbuf.append(a[0]);
    for (int i = 1; i < a.length; i++) {
      sbuf.append(", ");
      sbuf.append(a[i]);
    }
  }

  private MessageFormatter() {
  }
}
